Current and Emerging Laser Sensors for Greenhouse Gas Detection and Monitoring

Transcription

1 Physical Sciences Inc. VG Current and Emerging Laser Sensors for Greenhouse Gas Detection and Monitoring Presented by: Mickey B. Frish 20 New England Business Center Andover, MA MIRTHE Workshop on Air Monitoring in Energy Extraction August 9, 2013 Princeton University Princeton, NJ 20 New England Business Center Andover, MA 01810

2 Outline VG Needs and Applications for GHG Sensing Descriptions of Current Laser Sensing Technologies for CH 4 and CO 2 Near-IR vs Mid-IR Future applications for Mid-IR ICL/QCL Sensors Laser and detector technology development needs

3 VG NEEDS AND APPLICATIONS

4 Better Tools for GHG Science VG Good science demands good data Accurate, reliable widespread sensors Skilled people to operate sensors and interpret data Methane Concentrations at New York Botanic Garden Station Superstorm Sandy Is this an errant sensor or the real effect of Mother Nature??? Limaico, et. al, Urban Ambient Variability of Greenhouse Gases: A Year Assessment, MIRTHE Summer Workshop, August 2013, Tuesday Poster.

5 Anthropogenic CH 4 Natural Gas VG US natural gas system: Gathering >493,000 active natural-gas wells (90% use fracking) across 31 states in the U.S. in 2009 Transmission ~250,000 miles of pipeline,~ 1700 transmission stations,~17,000 compressors. Distribution gate stations,~132,000 surface metering and pressure regulation sites, >1,000,000 miles pipeline, >61,000,000 end-user customer meters. Maintaining the security and integrity of this system is a continual legally-regulated process of searching for, locating, and repairing leaks

6 CH 4 Fugitive Emissions Example VG Elevated methane concentrations on Boston streets measured by vehiclemounted mobile near-ir laser-based Cavity Ringdown Spectrometer. -- Attributed to leaky pipelines -- --Source : New York Times, Nov 20,2012

7 Natural Gas Leaks An Environmental Problem? VG American consumers are paying billions of dollars for natural gas that never reaches their homes, but instead leaks from aging distribution pipelines, contributing to climate change, threatening public health, and sometimes causing explosions. Total U.S. Unaccounted for Gas from Natural Gas Systems from a Total U.S. Reported Emissions from Natural Gas Distribution Systems from b Significant Incidents on U.S. Natural Gas Distribution Systems from c 2.6 trillion cubic feet of natural gas Equivalent to releasing 56.2 million metric tons of CO incidents / 116 fatalities / 465 injuries / $810,677,757 in property damage --- America Pays for Gas Leaks, Report Prepared for Senator Edward J. Markey, July But how much atmospheric methane anthropogenic vs biogenic? Sensors and science are needed!

8 Anthropogenic CO 2 Fossil Fuel Combustion VG Calculated fossil fuel CO 2 emissions all sectors power production, industrial, mobile, residential, commercial, and cement Project Vulcan, K. Gurney, Purdue University, Not illustrated: CO 2 pipelines 3900 miles existing CO 2 pipelines support enhanced oil recovery (EOR) Network emerging (~120,000 miles by 2050) to support carbon capture and sequestration (CCS)

9 Tools for Detecting GHG Sources VG Reliable, cost-effective tools are needed to: Monitor and map (spatially and temporally) sources of escaping CH 4 and CO 2 Provide sufficient sensitivity and resolution to distinguish local GHG sources from ambient Provide fast health and safety danger alerts Current and emerging tools include: Permanent or mobile/aerial trace gas detectors Permanent open-path sensors for fenceline monitoring Sensor networks for mapping ~ km 2 areas and measuring fluxes at surfaces and sub-surface downholes Future networks will comprise ~100s 1000s of inexpensive continuouslyoperated spatially and temporally correlated sensors

10 VG CURRENT LASER-BASED SENSORS

11 Tunable Diode Laser Absorption Spectroscopy (TDLAS) TDLAS is an active optical method for detecting and quantifying one or more analyte gases mixed with other gases Competitive Features Selective; generally insensitive to cross-species interference Sensitive; sub-ppm detection of many gas species Fast; sub-second response time Configurable; point, open-path, or standoff sensor Non-contact; only the probe beam need interact with the analyte VG Accepted as rugged, reliable, accurate commercial industrial sensors and analyzers Thousands currently in use Emerging high-volume market opportunities (process control, environmental monitoring) demand: reduced cost, simplicity, autonomy, reliability, and accuracy

12 TDLAS Technology Niche Near-IR TDLAS now fulfills many GHG sensor needs Near-IR is suitable and preferable for sensing many simple molecules Sensors utilize proven robust electronics platforms Reliable laser sources High precision Very low power consumption (< 1 W) Compact Minimal maintenance Acceptable cost; ~$10,000 per sensor unit Mid-IR interband cascade lasers (ICLs) and quantum cascade lasers (QCLs) enhance sensitivity over short paths Enables miniaturization and detection of trace pollutants and complex molecules Mass-produced chip-scale TDLAS sensors may enable future wide-area deployment of sensor networks Mid-IR Challenges: Low-noise uncooled mid-ir detectors Laser cost, power consumption, wavelength diversity, availability, reliability VG

13 Practical TDLAS Detection Limits for Some Gases VG ppm-m Near-IR (<2.2 μm) 2 to 3 m 4 to 8 m Gas 300 K Gas 300 K 300 K flames 300 K flames 1 atm 1 atm 1 atm 1 atm HF 0.2 HCN 1.0 H 2 S 20.0 CO NH CO H 2 O 1.0 NO CH NO HCl 0.15 O H 2 CO 5.0 C 2 H Mid-IR laser sources spanning wavelengths from 3-12 µm, enable sub-ppm-m detection of many complex hydrocarbons, TICS, and chemical agents Optical methods provide long optical path lengths to sense trace concentrations (~ ppbs) Open-path Multi-pass Herriot cell Resonant cavities Intra-cavity Optical Spectroscopy (ICOS) Cavity Ringdown Spectroscopy (CRDS) Solid-state nanoresonators

14 TDLAS Examples and GHG Sensing Applications VG Extractive: Localizing leaks in pipeline components such as valves and fittings. Point: Permanent installation at surface and subsurface or downhole sites. Open Path: Continuous and permanent pipeline health and safety monitoring. I n s t r u m e n t a t i o n S h a c k P r o c e s s i n g A r e a L a s e r T r a n s c e i v e r L a s e r B e a m 200 M e t e r s P a s s i v e R e t r o r e f l e c t o r In-situ: Monitoring and controlling CO 2 separation processes. O p t i c a l F i b e r a n d I n t e r f a c e C a b l e ( U p t o 1000 m C a b l e L e n g t h ) D z Standoff: Surveying pipelines or surface areas from walking, mobile, and aerial platforms.

15 Absorption Spectroscopy Fundamentals Gas molecules absorb light at specific colors ( absorption lines ) Beer-Lambert law where: I ν = I νo exp [S(T) g( - o ) N] = optical frequency (= c/l) o = line center frequency g() = lineshape function = path length N = absorbing species number density S(T) = temperature dependent linestrength I νo = unattenuated laser intensity I = laser intensity with absorption DI = change in intensity (= I 0 -I ) c = speed of light l = wavelength of light CH 4 Spectrum Mid-IR fundamental Near-IR overtone VG Absorbance = - ln (I /I o ) DI/I 0 ( with small DI) 200x linestrength advantage is the mid-ir appeal (when deployed judiciously)

16 Transmission TDLAS System Components VG Laser Absorbing Gas Detector Signal Processing Electronics Control Signals Focusing Optics Output d d Wavelength l o C-5215ez A frequency agile (i.e. tunable) laser beam transits an analyte gas sample Laser wavelength scans repeatedly across absorption line unique to analyte gas Received signal processed to deduce analyte concentration Laser sources SWIR Distributed Feedback (DFB) laser or SWIR Vertical Cavity Surface Emitting Laser (VCSEL) MWIR Interband Cascade Lasers LWIR Quantum Cascade Lasers

17 Portable Standoff near-ir TDLAS for Natural Gas Leak Survey VG Remote Methane Leak Detector (RMLD ) Commercial product (since 2005) Like a flashlight, laser beam illuminates a surface Senses analyte gas between transceiver and illuminated surface Standoff range ~100 ft with handheld transceiver Scanning laser beam across plume results in rapidly changing analyte gas measurement Can detect hazardous gas levels through windows for emergencies and responder safety ~2000 RMLDs in use for natural gas leak surveying; CO 2 version in demonstration

18 Other Standoff Configurations Manned Aerial Commercial Pipeline Leak Survey Service Mini-UAV Lab prototype for mapping landfill CH 4 emissions VG D. Picciaia et.al., Proceedings Sardinia 2011, Thirteenth International Waste Management and Landfill Symposium Portable Extractive New commercial product Mobile

19 Robust High-Precision Ambient CO 2 Sensor Dryer Diaphragm Pump VG Pressure Sensor Detector Module Measurement Cell AC-DC Power Supply DC Power and Signal Input Board WMS Board Laser & System Controller Near-IR (2.0 µm) ICOS design (~60m optical pathlength) Measures CO 2 mole fraction in dry air to 1:3000 with 1 minute averaging Applications: Monitoring CO 2 sources, sinks, and transport Sequestration site monitoring and leak detection

20 Thompson Farm Atmospheric Observatory Sensor Intercomparison, 3 31 July, 2008 VG Intercompared with UNH NDIR sensor Peaks occur at night when winds are calm, mixing is minimized and CO 2 from plant respiration builds up

21 [CO2] (ppm) Open-Path CO 2 PSI site, Andover, MA August 2011 VG LBNL s NDIR Near-Ground Point Sensor 1 5 m i n 0.1 Hz Noise signal Leak Alarm signal Tropical Storm Irene Start Labor Day Weekend Noise suppressor off 100 l/min CO 2 release Lost Data Log Signal Strength Near-IR Continuous operation No adjustment, calibration, or zeroing Diurnal variations correlate with point sensor measurements Leaking CO 2 yields statistically distinct signature Open-Path Transceiver and Control Unit CO 2 release source Point Sensor Apparatus

22 Pipeline Monitors 1 mile VG K-6090 Pipeline under road Permanent alarms to detect and mitigate small to potentially explosive leaks Near-IR Wireless Solar-powered Real-time alarm notification Easy installation & alignment Currently in demonstration 600 ft path Months of maintenance-free operation

23 Methane Open Path Data VG July 2013

24 VG EMERGING MID-IR SENSORS

25 FuelFinder VG Intended for locating leakage of refined petroleum products from buried distribution pipelines Primarily gasoline Laser Dewar Projected Beam InAs Photodetector and Preamp Collected Backscatter Receiver Primary Mirror 15 cm Side View Man-portable mid-ir backscatter TDLAS Wavelength ~3 µm Control Electronics 40 cm 12 mm Optical Breadboard Wall Plug Power RS-232 Interface Capitalizes on recent advances in Interband Cascade Lasers (ICLs) that operate at room temperature Projected Beam Collected Backscatter Laser Detector Primary Mirror 30 cm Top View Senses volatile complex hydrocarbon vapors F-8799

26 Miniature Low-Power Airborne CO 2 Sensor VG For airborne (UAV and balloon) CO 2 measurements A precise instrument rugged enough for the field and economical enough for widespread use by monitoring networks. Requirements: 1 ppmv ~0.1 Hz < 100 gm Battery power Deployable in an unconditioned payload Solution: Absorption spectroscopy using room-temperature mid-ir LED integrated with a miniaturized control and signal processing system

27 Vision Chip-scale Mass-Produced TDLAS Integrated-Optic Sensors and Networks Coupling Structure Laser Die Detector VG Solder Bond Pad Sensing Element Detector Electronics CMOS Substrate Thermally Stabilized Substrate K-4691 Naiini,M.M, et.al.,solid-state Electronics,74,58 (2012). Laser source, photodetector, and optical gas sampling element integrated on a miniature monolithic platform Each envisioned device senses one chemical; Several devices working in tandem sense several chemicals Novel gas sensing elements use solid-state optical waveguides Fabricated using established production techniques Complete assembly with electronics in cell-phone style package Cost ~ few $100 s when produced in quantities of hundreds of thousands or more Similar to proven commercial near-ir telecom products

28 Application Distributed Sensor Networks VG Central Processor 2 1 Each sensor detects one of a choice of several chemicals All sensors communicate wirelessly with a central processor Network provides wide area coverage and improves average sensitivity compared to individual sensors J-6764 (not to scale)

29 Cost Challenges Mickey s Mantra: TDLAS is not much more complex than compact disk players The smallest and lowest cost currently-available TDLAS sensors fit in a smoke-alarm type package weighing about three pounds Yet TDLAS sensors cost >$10,000 per unit, Despite laser chip costs that could be ~$50 -$100 each if designed for low-power spectrometry and produced in many tens of thousands VG Cost drivers Laser packages intended for telecommunications industry produced in relatively low each Bulk optical components Discrete component electronics Impact TDLAS today is too expensive, bulky, and power-hungry to deploy practically in distributed sensor networks

30 Technical Challenges VG Practical devices require improved power efficiency, specifically for laser and detector thermal control Solutions: Harness laser waste heat efficiently Design for uncooled detectors Smaller is better Detection goals require: Mid-IR lasers High-Q resonant sensing elements Simple optical coupling between sensor element, laser source, and detector

31 TDLAS Laser Sources vs. Needs Distributed FeedBack (DFB) Laser 14-pin butterfly package with integral thermo-electric cooler ~10 mw output power Optically-isolated fiber optic output ~ nm Electrical Connections Near-IR example Vertical Cavity Surface Emitting Laser (VCSEL) TO-8 package with integral thermo-electric cooler ~0.4 mw output power Fiber-coupling optional (w/reduced power) VG Transmitter Copper Submount Top View Optical Isolator Photodiode Fiber Tip Laser Lens Thermoelectric Cooler Side View Kovar Enclosure Cement-filled Tube Strain Relief Optical Fiber J-6640 Monolithic spectrometers need: µw s of laser power Stable, but not necessarily sub-ambient, laser temperature COTS Lasers are Overkill Need: Near and Mid-IR Lasers designed for widely-deployed gas sensing applications

32 Novel Packaging to Meet the Challenges Eliminate thermo-electric cooler (TEC) Heat, don t cool Proven in near-ir benchtop configuration VG Eliminate microlenses and optical isolator Enabled by monolithic integrated platform Simplify Electronics Reduce to ASIC

33 Summary VG Near-IR laser sensors for natural gas leak detection are established widely-accepted commercial technologies One of the largest laser-based gas sensing applications CO 2 sensors are available using similar sensor platforms Widely-deployed sensors for ubiquitous monitoring will benefit from mid-ir integrated optics Requires laser sources designed for gas sensing application Cost per laser <$100 in mass production Developing these sources is the challenge to the MIRTHE community